Cancellation includes battery (4)
I believe the answer is:
cell
'battery' is the definition.
(I've seen this in another clue)
'cancellation includes' is the wordplay.
'includes' indicates the answer is hidden within the clue.
'CELL' is hidden in the letters of 'cancellation'.
(Other definitions for cell that I've seen before include "Place of incarceration or unit of living matter" , "Microscopic unit of living matter" , "Dungeon" , "Small room for confining a prisoner" , "Prisoner's or monk's room" .)